The Short Answer
Temporary is a description of how you intend to use a building, not a planning category. A structure that stays put needs permission in the same way a permanent one does, whatever it is called and however quickly it can be dismantled.
There are three routes that avoid a full application, and each has hard limits. The 28-day rule, Class B permitted development, covers a temporary use of land for up to 28 days a year. Class A covers buildings needed for the duration of construction operations. Class H covers industrial and warehouse development on land already in industrial use, within defined size limits.
If none of those fits, it is a planning application, frequently for a temporary permission with an end date attached. That is a normal outcome rather than a failure, and it is worth planning for from the start rather than discovering at week six.
What the 28 Day Rule Covers
The 28-day rule is Class B of Part 4 of the General Permitted Development Order 2015. It is narrower than its reputation.
What Class B Permits
Class B permits the use of any land for any purpose for not more than 28 days in total in any calendar year, together with the provision on that land of any moveable structure for the purposes of that permitted use. Two things follow from how the 28-day rule is written. The right attaches to the use of land rather than to the building, and the 28 days are cumulative across the calendar year rather than per occasion.
The Curtilage Exclusion That Catches People Out
This is the one that ends most industrial enquiries. Class B is expressly not available where the land in question is a building or is within the curtilage of a building. A yard beside an existing warehouse or factory is normally inside that curtilage, which means the 28 day rule does not apply to the very place most temporary buildings are wanted. It is worth checking this before anything else, because it decides the route.
The 14 Day Sub-Limit
The 28 day rule carries a sub-limit inside it. Of the 28 days, no more than 14 in total may be used for holding a market or for motor car and motorcycle racing, including trials of speed and practice. Class B also excludes caravan siting, camping, the display of an advertisement, and certain uses on sites of special scientific interest.
Why 28 Days Is Rarely Enough Anyway
Even where the right is available, the arithmetic defeats most commercial requirements. A seasonal storage building covering a Q4 peak needs eight to twelve weeks. A building covering a refurbishment needs however long the refurbishment takes. Both are well beyond 28 days in a calendar year, so the 28 day rule that looked like a shortcut turns out not to be one. Seasonal cover of this kind is normally a temporary storage building on a permission rather than a permitted development right.
The Routes That Do Work
Three alternatives to the 28 day rule, in the order they are usually worth checking.
Part 4 Class A: Buildings Needed for Construction Operations
Class A permits buildings, moveable structures, works, plant or machinery required temporarily in connection with and for the duration of operations being carried out on that land or land adjoining it. It is the route for site workshops, covered storage and welfare space on a live construction project, and it is the one genuine alternative to the 28 day rule that most contractors can rely on. Two conditions attach: it does not apply where the operations are mining operations or where permission for those operations is required but not granted, and when the work finishes the structure must be removed and any adjoining land reinstated as soon as reasonably practicable.
Part 7 Class H: Industrial and Warehouse Permitted Development
Class H permits the erection, extension or alteration of an industrial building or warehouse on land already in industrial use, and it has real limits. A new building is capped at 200 square metres of gross floor space, or 100 on article 2(3) land such as conservation areas and National Parks, and on sites of special scientific interest. An extension to an existing building may not exceed the original by more than 50 per cent or 1,000 square metres, whichever is lesser, in ordinary cases. Nothing may sit within 5 metres of a boundary, height is capped at 5 metres within 10 metres of a boundary, and the development must not reduce parking or turning space. Most Noah spans exceed the 200 square metre new-build cap quickly, so this route suits smaller structures and attached extensions rather than a full warehouse.
A Temporary Planning Permission With an End Date
Where no permitted development right fits, an application is the answer, and authorities frequently grant a temporary permission with a condition requiring removal by a stated date. That is a good fit for a relocatable building and is often easier to obtain than a permanent consent on the same site, because the authority knows the position is reversible.
England, Wales and Scotland Are Not the Same
Every figure above is from the England order. Wales and Scotland operate their own permitted development regimes with different limits, and Northern Ireland differs again. Check the regime for the site rather than assuming the England position travels.
